Mode Localization and Suppressed Heat Transport in Amorphous Alloys
| Autor: | Davide Donadio, Giuseppe Barbalinardo, Nicholas W. Lundgren |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Fluids & Plasmas Alloy Population FOS: Physical sciences 02 engineering and technology engineering.material 01 natural sciences Molecular dynamics Thermal conductivity Engineering Lattice (order) 0103 physical sciences cond-mat.dis-nn 010306 general physics education education.field_of_study Condensed Matter - Materials Science Amorphous metal Condensed matter physics Materials Science (cond-mat.mtrl-sci) Disordered Systems and Neural Networks (cond-mat.dis-nn) Condensed Matter - Disordered Systems and Neural Networks 021001 nanoscience & nanotechnology cond-mat.mtrl-sci Amorphous solid Intermediate frequency Physical Sciences Chemical Sciences engineering 0210 nano-technology |
| Zdroj: | Physical Review B, vol 103, iss 2 |
| Popis: | Glasses usually represent the lower limit for the thermal conductivity of solids, but a fundamental understanding of lattice heat transport in amorphous materials can provide design rules to beat such a limit. Here we investigate the role of mass disorder in glasses by studying amorphous silicon-germanium alloy (a-Si$_{1-x}$Ge$_x$) over the full range of atomic concentration from $x=0$ to $x=1$, using molecular dynamics and the quasi-harmonic Green-Kubo lattice dynamics formalism. We find that the thermal conductivity of a-Si$_{1-x}$Ge$_x$ as a function of $x$ exhibits a smoother U-shape than in crystalline mass-disordered alloys. The main contribution to the initial drop of thermal conductivity at low Ge concentration stems from the localization of otherwise extended modes that make up the lowest 8\% of the population by frequency. Contributions from intermediate frequency modes are decreased more gradually with increasing Ge to reach a broad minimum thermal conductivity between concentrations of Ge from $x=0.25$ to $0.75$. 9 pages, 7 figures |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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